Is it permissible for an adult woman to shake hands with the ولي الأمر (ruler/head of state) at an awards ceremony or similar event?

It is not permissible for a woman to shake hands with a man who is a stranger to her. The Prophet, peace and blessings be upon him, used to give allegiance to women through words, without shaking hands, as evidenced by the narrations of Umm Ayman bint Ruqayyah and Aisha, may Allah be pleased with them. The Prophet, peace and blessings be upon him, forbade touching strange women, clarifying that for one of you to be stabbed in the head with an iron needle is better for him than to touch a woman who is not lawful for him, as stated in the narration of Ma'qil ibn Yasar.